1. Field of the Invention
The present invention relates to an electric-component holding apparatus which includes a holder-holding member and a component holder that is detachably attached to the holder-holding member and holds an electric component (e.g., electronic-circuit component or electronic component).
2. Discussion of Related Art
Generally, an electric-component (EC) holding apparatus includes a holder-holding member, and a component holder that is detachably attached to the holder-holding member. The EC holding apparatus may be attached to a movable member of an EC mounting device of an EC mounting system, and may be one which applies suction or negative pressure to an EC and thereby holds the EC, or one which includes a plurality of holding jaws to hold an EC. When the movable member is moved, the EC holding apparatus is moved to transfer the EC. In order that the component holder may be easily attached to, and detached from, the holder-holding member, an elastic member may be used. This elastic member can selectively take a removal preventing state in which the elastic member is engaged with both the component holder and the holder-holding member to prevent the component holder from removing from the holder-holding member, and a removal allowing state elastically deformed from the removal preventing state. If the component holder is moved relative to the holder-holding member by a force greater than a predetermined value in a direction in which the component holder may be attached to, and detached from, the holder-holding member, the elastic member is elastically deformed to allow the component holder to be attached to, or detached from, the holder-holding member. Thus, the component holder can be easily attached to, and detached from, the holder-holding member.
However, recently, it has been demanded to operate the EC mounting device at increased speeds to improve its EC mounting efficiency. Thus, the holder-holding member of the EC holding apparatus is started at increased accelerations and stopped at increased decelerations (i.e., negative accelerations). Therefore, the component holder may-come off the holder-holding member. More specifically described, the component holder is subjected to an inertia force equal to the product of an absolute value of an acceleration (or a deceleration) and a mass of the component holder, and thus the inertia force increases as the acceleration increases. When the inertia force overcomes the removal preventing force of the elastic member to prevent the component holder from removing from the holder-holding member, the component holder does remove from the holder-holding member. It is known that the phenomenon called “permanent set in fatigue” may occur to the elastic member because of increased times of use thereof or an increased time of lasting of elastic deformation thereof. In the latter case, the component holder is more likely to come off the holder-holding member. Moreover, if at least one of an engaging portion of the elastic member and an engaging portion of the component holder or the holder-holding member is worn out, then the component holder may be more likely to come off the holder-holding member.
While the above-described problems relate to the EC holding apparatus for use with the EC mounting system, the EC mounting apparatus encounters the same problems when the apparatus is used with various sorts of devices or systems that need to transfer ECs.